VT82C686B
Internal Keyboard Controller
Signal Name
Pin #
I/O
Signal Description
(Internal mouse controller enabled by Rx5A[1])
MultiFunction Pin
/ IRQ1
D5
IO / I
IO / I
IO / I
IO / I
MSCK
MSDT
KBCK
KBDT
Rx5A[1]=1
From internal mouse controller.
Mouse Clock.
Rx5A[1]=0
. Interrupt input 1.
Interrupt Request 1
/ IRQ12
C5
E5
A5
(Internal mouse controller enabled by Rx5A[1])
MultiFunction Pin
Rx5A[1]=1
Rx5A[1]=0
From internal mouse controller.
Mouse Data.
. Interrupt input 12.
Interrupt Request 12
/ A20GATE
/ KBRC
(Internal keyboard controller enabled by Rx5A[0])
MultiFunction Pin
Rx5A[0]=1
From internal keyboard controller
Keyboard Clock.
Rx5A[0]=0
Input from external keyboard controller.
Gate A20.
(Internal keyboard controller enabled by Rx5A[0])
MultiFunction Pin
Rx5A[0]=1
Rx5A[0]=0
From internal keyboard controller.
From external keyboard controller (KBC)
Keyboard Data.
Keyboard Reset.
for CPURST# generation
/ ROMCS# /
C1
O / O / I
I / IO
(Rx5A[0]=0). To external keyboard controller chip.
Keyboard Chip Select
KBCS#
strap
:
Power-Up Configuration Strap (Sampled At Reset)
4.7K to GND = Socket-7, 4.7K to VCC3 = Socket-370 / Slot-1
/ SD[7-4]
W4,
Y4,
V3,
W3
Sampled at reset on SD[7-4] and latched into
KBIN[6-3]
Keyboard Inputs 6-3.
Rx5A[7-4].
Chip Selects
Signal Name
/ KBCS# /
Pin #
I/O
Signal Description
C1
O
(Rx5A[0]=1). Chip Select to the BIOS ROM.
ROM Chip Select
ROMCS#
strap
:
Power-Up Configuration Strap (Sampled At Reset)
4.7K to GND = Socket-7, 4.7K to VCC3 = Socket-370 / Slot-1
/ GPO12 / XDIR
T5
O
(Rx76[1] = 1 and Rx8B[0] = 1). Asserted
Programmable Chip Select 0
PCS0#
during I/O cycles to programmable read or write ISA I/O port ranges.
Addressed devices drive data to the SD pins (XDIR is disabled and the X-
Bus is not implemented). See also Rx59[3] and Rx77[2].
/ GPO13 / SOE#
U5
U8
O
O
(Rx76[3] = 1, Rx76[4] = 0, Rx77[0] = 1).
Asserted during read or write accesses to I/O ports 62h or 66h.
MCCS#
MCCS#
Microcontroller Chip Select
/ GPI11 / GPO11
/ GPIOD
(Rx76[4] = 0 selects MCCS#
Microcontroller Chip Select (Alternate Pin)
on pin U8, Rx76[4] = 1 selects MCCS# on pin U5). Rx76[3] = 1 enables
MCCS# output on the selected pin.
Revision 1.71 June 9, 2000
-21-
Pinouts
ETC [ ETC ]
